rpc: Add exportasmap RPC

diff --git a/src/rpc/net.cpp b/src/rpc/net.cpp
index cf5e5864..5b19de10 100644
--- a/src/rpc/net.cpp
+++ b/src/rpc/net.cpp
@@ -9,12 +9,17 @@
 #include <banman.h>
 #include <chainparams.h>
 #include <clientversion.h>
+#include <common/args.h>
 #include <core_io.h>
+#include <hash.h>
 #include <net_permissions.h>
 #include <net_processing.h>
 #include <net_types.h>
 #include <netbase.h>
 #include <node/context.h>
+#ifdef ENABLE_EMBEDDED_ASMAP
+#include <node/data/ip_asn.dat.h>
+#endif
 #include <node/protocol_version.h>
 #include <node/warnings.h>
 #include <policy/settings.h>
@@ -25,6 +30,7 @@
 #include <rpc/util.h>
 #include <sync.h>
 #include <univalue.h>
+#include <util/asmap.h>
 #include <util/chaintype.h>
 #include <util/strencodings.h>
 #include <util/string.h>
@@ -1116,6 +1122,59 @@ static RPCMethod getaddrmaninfo()
     };
 }
 
+static RPCMethod exportasmap()
+{
+    return RPCMethod{
+        "exportasmap",
+        "Export the embedded ASMap data to a file. Any existing file at the path will be overwritten.\n",
+        {
+            {"path", RPCArg::Type::STR, RPCArg::Optional::NO, "Path to the output file. If relative, will be prefixed by datadir."},
+        },
+        RPCResult{
+            RPCResult::Type::OBJ, "", "",
+            {
+                {RPCResult::Type::STR, "path", "the absolute path that the ASMap data was written to"},
+                {RPCResult::Type::NUM, "bytes_written", "the number of bytes written to the file"},
+                {RPCResult::Type::STR_HEX, "file_hash", "the SHA256 hash of the exported ASMap data"},
+            }
+        },
+        RPCExamples{
+            HelpExampleCli("exportasmap", "\"asmap.dat\"") + HelpExampleRpc("exportasmap", "\"asmap.dat\"")},
+        [&](const RPCMethod& self, const JSONRPCRequest& request) -> UniValue {
+#ifndef ENABLE_EMBEDDED_ASMAP
+            throw JSONRPCError(RPC_MISC_ERROR, "No embedded ASMap data available");
+#else
+            if (node::data::ip_asn.empty() || !CheckStandardAsmap(node::data::ip_asn)) {
+                throw JSONRPCError(RPC_MISC_ERROR, "Embedded ASMap data appears to be corrupted");
+            }
+
+            const ArgsManager& args{EnsureAnyArgsman(request.context)};
+            const fs::path export_path{fsbridge::AbsPathJoin(args.GetDataDirNet(), fs::u8path(self.Arg<std::string_view>("path")))};
+
+            AutoFile file{fsbridge::fopen(export_path, "wb")};
+            if (file.IsNull()) {
+                throw JSONRPCError(RPC_MISC_ERROR, strprintf("Failed to open asmap file: %s", fs::PathToString(export_path)));
+            }
+
+            file << node::data::ip_asn;
+
+            if (file.fclose() != 0) {
+                throw JSONRPCError(RPC_MISC_ERROR, strprintf("Failed to close asmap file: %s", fs::PathToString(export_path)));
+            }
+
+            HashWriter hasher;
+            hasher.write(node::data::ip_asn);
+
+            UniValue result(UniValue::VOBJ);
+            result.pushKV("path", export_path.utf8string());
+            result.pushKV("bytes_written", (uint64_t)node::data::ip_asn.size());
+            result.pushKV("file_hash", HexStr(hasher.GetSHA256()));
+            return result;
+#endif
+        },
+    };
+}
+
 UniValue AddrmanEntryToJSON(const AddrInfo& info, const CConnman& connman)
 {
     UniValue ret(UniValue::VOBJ);
@@ -1210,6 +1269,7 @@ void RegisterNetRPCCommands(CRPCTable& t)
         {"network", &setnetworkactive},
         {"network", &getnodeaddresses},
         {"network", &getaddrmaninfo},
+        {"network", &exportasmap},
         {"hidden", &addconnection},
         {"hidden", &addpeeraddress},
         {"hidden", &sendmsgtopeer},
diff --git a/src/test/fuzz/rpc.cpp b/src/test/fuzz/rpc.cpp
index cd7f4987..f0362db2 100644
--- a/src/test/fuzz/rpc.cpp
+++ b/src/test/fuzz/rpc.cpp
@@ -78,15 +78,16 @@ const std::vector<std::string> RPC_COMMANDS_NOT_SAFE_FOR_FUZZING{
     "dumptxoutset",   // avoid writing to disk
     "enumeratesigners",
     "echoipc",              // avoid assertion failure (Assertion `"EnsureAnyNodeContext(request.context).init" && check' failed.)
+    "exportasmap",          // avoid writing to disk
     "generatetoaddress",    // avoid prohibitively slow execution (when `num_blocks` is large)
     "generatetodescriptor", // avoid prohibitively slow execution (when `nblocks` is large)
     "gettxoutproof",        // avoid prohibitively slow execution
-    "importmempool", // avoid reading from disk
-    "loadtxoutset",   // avoid reading from disk
-    "loadwallet",   // avoid reading from disk
-    "savemempool",           // disabled as a precautionary measure: may take a file path argument in the future
-    "setban",                // avoid DNS lookups
-    "stop",                  // avoid shutdown state
+    "importmempool",        // avoid reading from disk
+    "loadtxoutset",         // avoid reading from disk
+    "loadwallet",           // avoid reading from disk
+    "savemempool",          // disabled as a precautionary measure: may take a file path argument in the future
+    "setban",               // avoid DNS lookups
+    "stop",                 // avoid shutdown state
 };
 
 // RPC commands which are safe for fuzzing.
diff --git a/test/functional/feature_asmap.py b/test/functional/feature_asmap.py
index 310788f2..5debdfbe 100755
--- a/test/functional/feature_asmap.py
+++ b/test/functional/feature_asmap.py
@@ -11,11 +11,15 @@ with missing and unparseable files.
 The tests are order-independent.
 
 """
+import hashlib
 import os
 import shutil
 
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import assert_equal
+from test_framework.util import (
+    assert_equal,
+    assert_raises_rpc_error,
+)
 
 ASMAP = 'src/test/data/asmap.raw' # path to unit test skeleton asmap
 VERSION = 'bafc9da308f45179443bd1d22325400ac9104f741522d003e3fac86700f68895'
@@ -124,6 +128,29 @@ class AsmapTest(BitcoinTestFramework):
                     asns.append(asn)
         assert_equal(len(asns), 3)
 
+    def test_export_embedded_asmap(self):
+        self.log.info('Test exportasmap RPC')
+        export_path = os.path.join(self.datadir, "asmap.dat")
+
+        if not self.is_embedded_asmap_compiled():
+            assert_raises_rpc_error(-1, "No embedded ASMap data available", self.node.exportasmap, export_path)
+            return
+
+        # Relative paths are resolved against the datadir.
+        result = self.node.exportasmap("asmap.dat")
+        assert_equal(result["path"], export_path)
+
+        with open(export_path, 'rb') as f:
+            data = f.read()
+        assert_equal(result["bytes_written"], len(data))
+
+        # Added in https://github.com/bitcoin/bitcoin/pull/34696
+        expected_hash = "478d61986c59365cf86cd244485bbbe76a9ca0c630864717286dd19949879074"
+        assert_equal(hashlib.sha256(data).hexdigest(), expected_hash)
+        assert_equal(result["file_hash"], expected_hash)
+
+        os.remove(export_path)
+
     def run_test(self):
         self.node = self.nodes[0]
         self.datadir = self.node.chain_path
@@ -139,6 +166,7 @@ class AsmapTest(BitcoinTestFramework):
         self.test_asmap_with_missing_file()
         self.test_empty_asmap()
         self.test_asmap_health_check()
+        self.test_export_embedded_asmap()
 
 
 if __name__ == '__main__':